#include <stdio.h>
#include <algorithm>

using namespace std;

#define MAX_N 1005
#define MAX_V 50005
#define FIN "economie.in"
#define FOUT "economie.out"

int N, V[MAX_N], sol[MAX_N], ns;
char can[MAX_V];

int main(void)
{
    int i, j;

    freopen(FIN, "r", stdin);
    freopen(FOUT, "w", stdout);

    scanf("%d", &N);
    for (i = 0; i < N; ++i)
        scanf("%d", V+i);

    sort(V, V+N);
    for (can[0] = 1, i = 0; i < N; ++i)
    {
        if (can[V[i]]) continue;
        sol[ns++] = V[i];
        for (j = 0; j+V[i] < MAX_V; ++j)
            can[j+V[i]] |= can[j];
        for (j = i+1; j < N; ++j)
            if (!can[V[j]]) break;
        if (j == N) break;
    }
    printf("%d\n", ns);
    for (i = 0; i < ns; ++i)
        printf("%d\n", sol[i]);

    return 0;
}